We might not, but denying the possibility only guarantees we move further away from it.
It's even darker than that. There is an organized effort to destroy any public forum that is a place of discourse. For the people and organization paying for the bots, troll farms and social media influencers discourse is exactly what they paying to get rid of. Considering that reddit doesn't have any other business model they had to start fighting back.
in this case, user/advertiser metrics
On what grounds do you base your own sense of "rationality and clear argument" as superior to that of the apparent majority of people that you refer to as "the cesspool"?
In my experience, the majority is "I don't have any interest in arguing." Leaving the cesspool to those few who do want to argue.
If you believe that either (a) arguments against such people less clear and rational than the racists' arguments, or (b) such people are actually in the majority, then I believe we disagree on things so fundamental we can't have a constructive debate about Reddit's policies.
I still disagree though - I think Reddit probably agreed with you for most of its existence, but evidence indicated that rationality and clear arguments weren't winning, and the virality of these ideas was too potent to be overcome by a few people who were willing to wade into the cesspool. So they drained the cesspool.
I agree with you that, if we could be sure that there would always be enough people to argue against racists, and do so calmly and rationally, then we would be better off not censoring racism, and instead letting the debate play out. But I don't think we live in that world.